A semiconductor chip such as a memory chip cutout from a semiconductor wafer is generally mounted on a printed substrate or the like in a packaging condition. However, an outer size of a package is considerably larger than the size of a various types of the semiconductor chips themselves and therefore, there is a certain limit in the number of the packages mountable on the printed substrate or the like.
On the other hand, recently, a multichip module (MCM), in which a plurality of semiconductor chips are mounted on the substrate, is being popularized. Using the multichip module allows the followings: (1) miniaturization of a mounting area and weight reduction accompanying with this, (2) realization of a high performance and high speed by high density wiring and bear chip mounting, and (3) keeping high reliability.
By the way, in the multichip module capable of a high density mounting described above, a plurality of semiconductor chips are mounted on a single substrate and therefore, a defect ratio of respective semiconductor chips is accumulated to make a total defect ratio of the module large. For example, in the case where four memory chips are implemented on a single module substrate, only one defect memory chip causes overall defect of the module. Therefore, it is necessary handling to replace the defect memory chip as a repairing work and discard the overall module as a defect product. Thus, a low yield and a low efficiency occur. In addition, in the case where a plurality of semiconductor chips are mounted on a single substrate, each one of respective chips is mounted on a single substrate to complicate a manufacturing process.